PBAT/PCL共混薄膜在草莓保鲜包装中的应用

目的通过聚己内酯(PCL)来改善聚己二酸-对苯二甲酸丁二酯(PBAT)的自粘性、成膜性及气体透过性,探究不同厚度和不同气体透过性的PBAT/PCL共混薄膜包装对新鲜草莓的保鲜效果。方法利用双螺杆挤出流延机组制备不同厚度和不同气体透过性的PBAT/PCL共混薄膜,并用于草莓的密闭包装。结果纯PBAT的自粘性由于PCL的添加得到改善,且不同厚度及共混比例的PBAT/PCL共混薄膜气体透过量不同,但CO_2/O_2选择透过比几乎不变。当薄膜用于草莓包装时,PBAT/PCL20薄膜草莓包装内部的CO_2浓度从第2天开始迅速进入平衡状态,维持在体积分数为2%~3%的范围,而O_2的体积分数随着贮藏时间逐渐降低后达到6%~7%。结论少量PCL的添加可改善PBAT的自粘性,一定厚度和透过性的PBAT/PCL共混膜可以使包装内部建立起低氧高二氧化碳的气氛环境,抑制草莓的呼吸作用,延长其保鲜期。

Application of Modified Poly(Butylene Adipate-co-butylene Terephthalate)/ Poly(Caprolactone) Blending Film in Fresh-Keeping Packaging of Strawberry

The work aims to study the PBAT/PCL blending film with different thicknesses and gas permeability on the fresh-keeping effect of fresh strawberries by improving the autohension, film formation and gas permeability of poly(butylene adipate-co-butylene terephthalate) (PBAT) by poly(caprolactone) (PCL). PBAT/PCL blending films with different thicknesses and different gas permeability were prepared by twin-screw extruder and casting machine. The blending films were used for the airtight packaging of strawberries. The autohension of pure PBAT was improved with the addition of PCL. The gas permeance of PBAT/PCL blending films with different thicknesses and blending proportions was different, but the selective-permeability of CO2/O2 remained almost unchanged. When the films were used for strawberry packaging, the CO2 concentration inside the PBAT/PCL20 film package for strawberries rapidly began to enter a balanced state from the second day and the volume fraction maintained within 2%~3%. However, the volume fraction of CO2 was gradually reduced with the storage time and then reached 6%~7%. The autohension of PBAT can be improved with the addition of a small amount of PCL. The PBAT/PCL blending film with certain thicknesses and permeability enables the atmospheric environment of hypoxia and hypercapnia to be built inside the package, inhibits the respiration and prolongs the shelf life of the strawberries.